Crystallographic Mirror Plane Research Articles

4,4-Difluoro-1,3,5,7-tetramethyl-8-pentafluorophenyl-4-bora-3a,4a-diaza-s-indacene

In the title dye compound, C19H14BF7N2, the boron–dipyrromethene core lies on a crystallographic mirror plane which bis­ects the BF2 and penta­fluoro­phenyl groups. The dihedral angle between the penta­fluoro­phenyl ring and the tricyclic system is thus 90° by symmetry. The sp 3-hybridized B atom has a slightly distorted tetra­hedral coordination.

Crystal structure and stability of Tl2CO3at high pressures

The crystal structure of dithallium carbonate, Tl(2)CO(3) (C2/m, Z = 4), was investigated at pressures of up to 7.4 GPa using single-crystal X-ray diffraction in a diamond anvil cell. It is stable to at least 5.82 GPa. All atoms except for one of the O atoms lie on crystallographic mirror planes. At higher pressures, the material undergoes a phase transition that destroys the single crystal.

2-Iodo-4,6-dimethylpyrimidine

In the title compound, C6H7IN2, the non-H atoms of the mol­ecule are located on a crystallographic mirror plane; the H atoms of the methyl groups are therefore disordered over two positions of equal occupancy. In the crystal structure, short inter­molecular I⋯N contacts [3.390 (3) Å] are found, linking the mol­ecules into zigzag chains. In addition, there are inter­molecular π–π stacking inter­actions between the pyrimidine rings of adjacent mol­ecules [centroid–centroid distance = 3.5168 (10) Å], resulting in a two-dimensional supra­molecular architecture.

Trans-Chlorido(dimethyl sulfoxide-κS)(pyridine-2-carboxylato-κ2N,O)platinum(II)

In the title complex, [Pt(C6H4NO2)Cl(C2H6OS)], the PtII ion is in a distorted square-planar environment defined by the N and O atoms from the chelating pyridine-2-carboxyl­ate (pic) anionic ligand, one S atom of the dimethyl sulfoxide mol­ecule and one Cl ion. The complex is disposed about a crystallographic mirror plane parallel to the ac plane passing through all the atoms of the complex except the methyl atoms of the dimethyl sulfoxide. The mol­ecules are stacked in columns along the b axis with a Pt⋯Pt distance of 4.9508 (5) Å. Within the column, inter­molecular C—H⋯O hydrogen bonds and weak π–π inter­actions between adjacent pyridine rings are present, the shortest centroid–centroid distance being 5.153 (4) Å.

Guanidinium 4-aminobenzoate

In the title compound, CH6N3 +·C7H6NO2 −, the cation and anion lie on crystallographic mirror planes. The 4-amino­benzoate anion is almost in a planar conformation with a maximum deviation of 0.024 (2) Å for the N atom. The bond length in the deprotonated carboxyl group is inter­mediate between those of normal single and double Csp2=O bonds, indicating delocalization of the charge over both O atoms of the COO− group. In the crystal, N—H⋯O hydrogen bonds assemble the ions in layers propagating in the bc plane. This structure is very similar to that of guanidinium benzoate.

Redetermination of diammonium thiomolybdate

In contrast to the previous structure determinations of the title structure, (NH4)2[MoS4], the present determination at 173 K localized the positions of the H atoms. The title structure belongs to the β-K2SO4 family and all the ions are located on crystallographic mirror planes. The ions are held together by N—H⋯S hydrogen bonds (some of which are bifurcated), forming a three-dimensional network. One of the N atoms has nine contacts to the S atoms shorter than 4 Å, and the other has ten.

Poly[(μ2-3,6-di-4-pyridyl-1,2,4,5-tetrazine)(μ2-thiocyanato)copper(I)

The title compound, [Cu(NCS)(C12H8N6)]n, is a self-assembled two-dimensional metal–organic network. The Cu atom is linked by two N atoms from two 3,6-di-4-pyridyl-1,2,4,5-tetra­zine ligands and by the N and S atoms from two thio­cyanate ligands in a distorted tetra­hedral environment. The Cu atom and the thio­cyanate ligand occupy a crystallographic mirror plane m, and a crystallographic inversion centre is in the middle of the tetra­zine ring, generating the zigzag fashion of the two-dimensional network. The infinite –Cu—SCN—Cu—SCN– chain is due to translational symmetry along the a axis. These chains are further connected through the 3,6-di-4-pyridyl-1,2,4,5-tetra­zine ligands that bridge the CuI centers, generating a two-dimensional network. There are π—π stacking inter­actions between the pyridine and tetra­zine rings (perpendicular distances of 3.357 and 3.418 Å), with a centroid–centroid distance of 3.6785 (16) Å.

Poly[[di-μ-aqua-(μ-4-formyl-2-methoxyphenolato)disodium] 4-formyl-2-methoxyphenolate

In the title coordination polymer, {[Na2(C8H7O3)(H2O)4](C8H7O3)}n, all the non-H atoms except the water O atoms lie on a crystallographic mirror plane. One sodium cation is bonded to four water O atoms and one vanillinate O atom in a distorted square-based pyramidal arrangement; the other Na+ ion is six-coordinated by four water O atoms and two vanillinate O atoms in an irregular geometry. One of the vanillinate anions is directly bonded to two sodium ions, whilst the other only inter­acts with the polymeric network by way of hydrogen bonds. In the crystal, a two-dimensional polymeric array is formed; this is reinforced by O—H⋯O hydrogen bonds, which generate R 2 1(6) and R 2 2(20) loops.

Catena-Poly[[(4-aminobenzoato)aquasilver(I)]-μ-hexamethylenetetramine

In the title coordination polymer, [Ag(C7H6NO2)(C6H12N4)(H2O)]n, the AgI ion is five-coordinated by two carboxyl­ate O atoms from one 4-amino­benzoate anion (L), two N atoms from two different hexa­methyl­enetetramine (hmt) ligands, and one water O atom in a distorted square-pyramidal geometry. The metal atom lies on a mirror plane and the L anion, hmt ligand and water mol­ecule all lie across crystallographic mirror planes. Each hmt ligand bridges two neighboring AgI ions, resulting in the formation of a chain structure along the b axis. The chains are linked into a three-dimensional framework by N—H⋯O and O—H⋯O hydrogen bonds.

2-(2-Pyridylsulfanyl)acetic acid

All non-H atoms of the title compound, C7H7NO2S, lie on a crystallographic mirror plane, with the two methyl­ene H atoms bis­ected by this plane. The crystal packing is characterized by inter­molecular C—H⋯O and O—H⋯N contacts, which link the mol­ecules into infinite zigzag chains parallel to [010].

Tris(4-tert-butylphenyl)phosphine oxide

In the title compound, C30H39OP, the P=O bond length is 1.4866 (12) Å and the P—C bond lengths range from 1.804 (2) to 1.808 (13) Å. The molecle is located on a crystallographic mirror plane. The methyl groups of one tert-butyl group are disordered over two sites in a 0.776 (4):0.224 (4) ratio.

5-Methylisoxazole-4-carboxylic acid

In the title compound, C5H5NO3, the mol­ecule lies on a crystallographic mirror plane with one half-mol­ecule in the asymmetric unit. An intramolecular C—H⋯O inter­action is present. In the crystal, strong inter­molecular O—H⋯N hydrogen bonds result in the formation of a linear chain structure along [100], and there are also weak C—H⋯O hydrogen bonds between the chains which help to stabilize the crystal packing.

Aqua{4,4′-dibromo-6,6′-dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato}copper(II)

The title complex, [Cu(C18H16Br2N2O4)(H2O)], lies on a crystallographic mirror plane with the CuII ion coordinated by two N atoms and two O atoms of a tetra­dentate Schiff base ligand and one O atom from a water ligand in a slightly distorted square-pyramidal environment. The mirror plane, which coincides with the Cu—Owater bond, imposes disorder of the atoms of the ethyl­ene group. In the crystal structure, inter­molecular O—H⋯O hydrogen bonds link complex mol­ecules into extended chains along [100].

4,5-Dichloro-2-methylpyridazin-3(2H)-one

The asymmetric unit of the title compound, C5H4Cl2N2O, contains one half-mol­ecule: all the non-H atoms lie on a crystallographic mirror plane. In the crystal structure, mol­ecules are linked into chains along the c axis by weak inter­molecular C—H⋯O hydrogen bonds.

(3,5-Dimethylpyrazol-1-yl)[5-(3,5-dimethylpyrazol-1-ylcarbonyl)-2-thienyl]methanone

The title compound, C16H16N4O2S, crystallizes with two symmetry-independent half-mol­ecules in the asymmetric unit. All non-H atoms in each molecule lie in a crystallographic mirror plane. The mol­ecules form sheets in the ac plane, which then form stacks along the b axis. The sheets are connected via π–π stacking inter­actions [centroid–centroid distance between pyrazolato rings = 3.6949 (8) Å].

4,6-Dimethyl-2-p-tolylpyrimidine

The mol­ecule of the title compound, C13H14N2, is located on a crystallographic mirror plane. The aromatic rings make a dihedral angle of 3.4 (2)°. The H atoms of the methyl groups on the benzene ring are disordered over two positions; their site-occupation factors were fixed at 0.5. In the crystal, inter­molecular C—H⋯π contacts form infinite chains perpendicular to the b axis.

2-Bromo-4-chloro-6-(cyclopentyliminomethyl)phenol

All atoms of the title mol­ecule, C12H13BrClNO, except the C and H atoms of the cyclo­pentane methyl­ene groups lie on a crystallographic mirror plane. The cyclo­pentane ring adopts an envelope conformation and an intra­molecular O—H⋯N hydrogen bond is observed. In the crystal, mol­ecules are stacked along the b axis by π–π inter­actions [centroid–centroid distance = 3.6424 (11) Å].

Bis[4-(dimethylamino)pyridine-κN1]silver(I) nitrate dihydrate

The title compound, [Ag(C7H10N2)2]NO3·2H2O or [Ag(dmap)2]NO3·2H2O, where dmap is 4-(dimethyl­amino)­pyridine, has a distorted linear coordination geometry around the AgI ion. A novel pattern of water–nitrate hydrogen-bonded anionic strands is formed in the c direction, with the cationic [Ag(dmap)2]+ monomers trapped between them. The AgI ion and the nitrate group atoms, as well as the water mol­ecules (including the H atoms), are on a crystallographic mirror plane (Wyckoff position 4a). The influence of bulky methyl substituents in position 4 of the 4-(dimethyl­amino)­pyridine ligand on packing is discussed. The absolute structure was determined unequivocally.

Ethylenediammonium tetrabromidomercurate(II) monohydrate

The HgII atoms in the crystal structure of the title compound, (C2H10N2)[HgBr4]·H2O, are tetra­hedrally coordinated by four Br atoms and the resulting [HgBr4]2− ions are inter­connected to the [NH3—CH2—CH2—NH3]2+ ions and water mol­ecules by N—H⋯Br and O—H⋯Br bonds, forming a three-dimensional network. N—H⋯O inter­actions are also present. The observed three different Hg—Br distances of 2.5597 (6), 2.6862 (8) and 2.6923 (8) Å in the tetra­bromo­mercurate unit are due to the connection of Br atoms to different numbers of H atoms. The Hg, O and two Br atoms are located on a crystallographic mirror plane. The cation has symmetry with the center of the C—C bond lying on a crystallographic center of inversion.

Bis[μ-5-(2-pyridyl)tetrazolato]-κ3N1,N5:N2;κ3N2:N1,N5-bis[triaquazinc(II)] bis(trifluoroacetate) monohydrate

The title compound, [Zn2(C6H4N5)2(H2O)6](CF3CO2)2·H2O, was synthesized by hydro­thermal reaction of ZnBr2, CF3COOH and 2-(2H-tetra­zol-5-yl)pyridine. The ZnII cation is coordinated by one N atom from the 5-(2-pyrid­yl)tetra­zolate anion, two N atoms from another 5-(2-pyrid­yl)tetra­zolate anion and three O atoms from three water mol­ecules in a distorted octa­hedral geometry. The tetra­zole ligands bridge the metal ions of the dimeric structure, and the dimers are located on crystallographic inversion centers. An inter­stitial solvent water mol­ecule is located on a crystallographic mirror plane, and the CF3COO− counter-anions are also not coordinated to the metal complex. The F atoms of the anions are disordered with the F atoms statistically distributed over two positions in a 0.56 (3)/0.44 (3) ratio. All the water H atoms are involved in O—H⋯N and O—H⋯O hydrogen bonds with uncoordinated water O atoms, carboxyl­ate O atoms and tetra­zole N atoms. The inter­actions link the mol­ecules into a three-dimensional network.